Year	constant 2011 PPP $ per kg of oil equivalent
1994	4.04868325162028
1995	4.6972768521426
1996	7.5991102892098
1997	6.61484859237934
1998	6.15249502111931
1999	6.81422338263434
2000	5.48137638334776
2001	5.92161962525089
2002	5.94377768139312
2003	6.19169688774357
2004	6.00911811104381
2005	6.23616305688962
2006	6.25141345957306
2007	6.61242866245936
2008	6.20245986214254
2009	5.76856766065388
2010	5.58198979237715
2011	5.11166078238503
2012	5.41971121157487
2013	5.74483217005445
2014	4.79330156712986